Shock. Scott G. Sagraves, MD, FACS Assistant Professor Trauma & Surgical Critical Care Associate Director of Trauma UHS of Eastern Carolina. Objectives. Define & classify shock Outline management principles Discuss goals of fluid resuscitation
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Scott G. Sagraves, MD, FACS
Trauma & Surgical Critical Care
Associate Director of Trauma
UHS of Eastern Carolina
“A momentary pause in the act of death.”
-John Collins Warren, 1800s
SHOCK: inadequate organ perfusion to meet the tissue’s oxygenation demand.
“Hypoperfusion can be present in the absence of significant hypotension.”
ATP + H2O ADP + Pi + H+ + Energy
Acidosis results from the accumulation of acid when during anaerobic metabolism the creation of ATP from ADP is slowed.
H+ shift extracellularly and a metabolic acidosis develops
Pulmonary A. pressure
Stroke volume index
60 yo male
CO = 4.0 L/min
BSA = 1.86
CI = 2.4 L/min/m2
60 yo male
CO = 4.0 L/min
BSA = 2.64
CI = 1.5 L/min/m2
PAOP = 9
RA = 5
RV = 22/4
Cardiac Index (CI)2.8 - 4.2
Stroke Volume Index (SVI)30 - 65
Sys Vasc Resistance Index (SVRI)1600 - 2400
Left Vent Stroke Work Index (LVSWI)43 - 62
C.I. = HR x SVI
SVI measures the amount of blood ejected by the ventricle with each cardiac contraction.
Total blood flow = beats per minute x blood volume ejected per beat
MAP - CVP
SVR = vasoconstriction
SVR = vasodilation
MPAP - PAOP
PVR = constriction
Vascular resistance = change in pressure/blood flow
LVSWI = (MAP-PAOP) x SVI x 0.0136
normal = 43 - 62
VSWI describe how well the ventricles are contracting and can be used to identify patients who have poor cardiac function.
ventricular stroke work = pressure x vol. ejected
Demand > consumption = anaerobic metabolism
Demands are met
The critical value is variable
& is dependent upon the patient, disease, and the metabolic demands of the patient.
Arterial Oxygen Content (CaO2)
Venous Oxygen Content (CvO2)
Arteriovenous Oxygen Difference (avDO2)
Efficiency of the oxygenation of blood and the rates of oxygen delivery and consumption
CaO2 = (1.34 x Hgb x SaO2) + (PaO2 x 0.0031)
If low, check hemoglobin or pulmonary gas exchange
avDO2 = CaO2 - CvO2
Values > 5.6 suggests more complete tissue oxygen extraction, typically seen in shock
O2AVI = CI x CaO2 x 10
Normal values suggests that the heart & lungs are working efficiently to provide oxygen to the tissues.
< 400 is bad sign
VO2I = CI x (CaO2 - CvO2)
If VO2I < 100 suggest tissues are not getting enough oxygen
NOT ALL PATIENTS CAN ACHIEVE THESE GOALS
Critically ill patients who can respond to their disease states by
spontaneously or artificially meeting these goals do show a
“Shock is a symptom of its cause.”
Coronary PP = DBP - PAOP
coronary perfusion = P across coronary a.
GOAL - Coronary PP > 50 mm Hg
DISTRIBUTIVE or N varies
What do you think...
ADJUST YOUR WEDGE FOR THE PEEP
Shock: “rude unhinging of the machinery of life.”
-Samuel D. Gross, 1872